Upload
doankhuong
View
234
Download
4
Embed Size (px)
Citation preview
CELL STRUCTURE
AND FUNCTIONTextbook Connection McDougal Littell “Biology” 1.1, 3.1-3.2, 18.5
Revised 2012-2013
Objectives:
1. Differentiate between prokaryotic and
eukaryotic cells.
2. Describe the internal structure of eukaryotic
cells.
3. Summarize functions of organelles in plant
and animal cells.
4. Differentiae between unicellular and
multicellular organisms.
Prokaryotic Cells
primitive, ‘before kernal’
- NO NUCLEUS
Lack internal membranes (no “membrane-bound” organelles)
Genetic material: single, circular DNA molecule suspended in the cytoplasm
Ex. Bacteria
(such as Anthrax or E. coli)
Microscopic, single-celled organisms
Prokaryotic Cells (Bacteria)
Prokaryotic Cells
Cell structures:
Cell Wall
DNA
Cell Membrane
Ribosomes
Cytoplasm
Prokaryotic Cells (Bacteria)
Bacteria live on or in just about every material and environment on Earth
from soil to water to air, and from your house to arctic ice to volcanic
vents.
•Each square centimeter of your skin averages about 100,000
bacteria.
•A single teaspoon of topsoil contains more than a billion
(1,000,000,000) bacteria.
•A shovel full has as many bacteria as there are people on Earth.
http://www.microbe.org/mi
crobes/bacterium1.asp
Prokaryotic Cells (Bacteria)
Prokaryotic Cells (Bacteria)
This is Streptococcus pyogenes
which is the organism responsible
for Strep Throat, Rheumatic Fever
and Impetigo (also known as
FLESH EATING BACTERIA!).
•It has been with us for
centuries and looks like it will
continue to be, but it is not a
major concern for the entire
human race as some of the
tabloids might have you
believe.
You may find this one appetizing!.
A gram of the toxin from this
organism is a lethal dose for
200,000 mice.
•A cup of this toxin in pure form
would be capable of
depopulating the entire Earth.
•This organism is Clostridium
botulinum , the organism
responsible for Botulism.
Information from http://www.dmacc.cc.ia.us/instructors/scottie.htm
Bacteria thrive in warm, moist
environments.
•Wearing headphones for just
one hour will increase the
amount of bacteria in your ear
by 700 times.
Ready to move on??
•The toxin, called botulin works like nerve gas causing respiratory
failure, paralysis and death in as little as 4 hours.
•It can be found in improperly prepared canned foods.
Beneficial Bacteria
Not all bacteria are bad.
Humans and Other Animals:
More bacterial cells in us and on us than there
are human cells.
In the gut:
Provide nutrients: break down food, make vitamins.
Keep away harmful microbes by filling niches that
would be filled by disease-causing bacteria.
Help chemically beak down dairy products to yogurt
and cheese, cucumbers to pickles, to make soy
sauce and vinegar.
Beneficial Bacteria
Ecosystems:
Produce oxygen, recycle carbon, nitrogen,
hydrogen and sulfur.
Helps make minerals in the soil for plant
growth.
Bioremediation: break down pollutants (ex.
Oil)
Recycling and composting: biodegradable
often means it can be broken down by
bacteria.
CELL STRUCTURE AND FUNCTION
Eukaryotic Cells (you-carry-ee-AHT-ihk),
‘true kernal’ contains a “TRUE NUCLEUS”
Membrane bound (enclosed) organelles
Genetic material: located in the nucleus.
Multi-cellular and single-cellular organisms
What do YOU think?
What characteristics are shared by most
cells?
In what ways are cells similar to atoms?
Types of Eukaryotic Cells:
Animal Cells
Plant Cells
•Both types have many of
the same internal parts but
there are also a few parts
unique to either just plants or
just animals.
•Lets start with the parts
common to both types…
Major Parts of the
Eukaryotic Cell:Cell Membrane
Nucleus
Ribosomes
Cytoplasm
Endoplasmic
Reticulum
Golgi Apparatus
Vesicles
Mitochondria
Lysosomes
Centrosome
Cell Wall
Chloroplast
Water Vacuole
Cell Membrane: “Security
Gate” Surrounds the cell
Controls movement of
materials into and out of
cell
Cytoplasm: “cyto”=something belonging to a
cell.
Fills space between cell
membrane and nucleus.
Maintains cell structure
Where many chemical
reactions take place.
Made up of 2 parts
1) Cytosol: the fluid
environment
Mostly water
2) Cytoskeleton:
Network of protein fibers
crisscrossing the cytoplasm
that constantly change to meet
the needs of the cell.
Give shape of the cell
Anchors its organelles
and serves as a “track”
for them to move on.
Enable cells to move
and divide.
Help muscle cells
contract and relax.
Organelles: subcellular structures
• Structures specialized to perform distinct
processes.
• Most are surrounded by membranes
Organelles involved in making proteins
Nucleus
Ribosomes
Endoplasmic
Reticulum
Vesicles
Golgi Apparatus
Nucleus: “Brain”
Controls the functions of the cell
Stores and protects genetic info
(DNA)
DNA contains genes which are the
instructions for making proteins.
Includes the following:
Nuclear Envelope (Membrane):
Double membrane folded upon itself
to create a space in between. It
controls movement into and out of
the nucleus
Nuclear Pore: holes which allow
movement between nucleus and
cytoplasm.
Nucleus:
Nucleolus: Dense
region inside nucleus,
where and ribosomes
are assembled
Chromatin: Genetic
Material (DNA) which
is organized into
structures called
chromosomes during
cell division.
Endoplasmic Reticulum
(ER): “Highway” Interconnected network of channels…aids in movement of
molecules inside the cell.
Rough ER:
Ribosomes found on surface.
Proteins leave ribosome
and enter into ER where they
are modified.
Smooth ER:
No ribosomes on surface.
Make lipids (fats)
Break down drugs and
alcohol.
Vesicles: “Semi-Trucks”
Small membrane-enclosed sacs
Transport molecules from place to place (ex. ER to
Golgi Apparatus.
Ribosome: “Factory”
Makes proteins and found in the cytosol (used for cell membrane or
secreted) or on the ER (used in chemical reactions in cell).
NOT Organelles
Golgi Apparatus (Complex): “packaging
and distributing center” Stack of membrane-enclosed spaces.
Process/Sorts/Packages protein/lipids for distribution within the cell
and export out of the cell.
Proteins/lipids come from endoplasmic reticulum.
What do YOU think?
What is distinctive about the nuclear membrane? Why
is it described as an envelope?
Suppose a certain poison kills human cells by blocking
pores in the nuclear membrane. Explain why it would
or would not kill bacteria.
Medicine, alcohol and many drugs are detoxified in liver
cells. Why do you think the liver cells of some people
who abuse alcohol and drugs have an increased
amount of smooth ER?
Mitochondria
Vacuole
Lysosomes
Centrosomes
Cell wall
Chloroplasts
Central Water Vacuole
Part IV: Other organelles:
Mitochondria: “Powerplant”
Provides energy for cell.
Converts food to usable energy for cell.
Have their own ribosomes and DNA.
Vacuole: “Storage Tanks”
Fluid filled sack.
Stores water, food
molecules, ions and
enzymes.
Animal cells contain many
small vacuoles.
Plant cells contain a large
central vacuole…we will
be talking about this more
later…
Lysosomes: “Suicide Sacs/Recycling Centers”
Carry enzymes to destroy cellular
waste.
Break down damaged/worn
out cell parts.
Engulf/digest targeted molecules
Defend cell from invading
bacteria/viruses
Once thought to be only in animal
cells, but exist minimally in plant
cells.
Membrane protects cell from
enzymes.
Animal Cells contain all of the previous organelles plus:
Centrioles: 2 cylindrical organelles (together called a
centrosome)
Formed by hollow protein fibers called microtubules (part of the
cytoskeleton)
Produce microtubules that aid in
moving chromosomes during cell
division.
Found in animals and algae only
but not in all animal cells.
Video tour of cell
Plant Cells:
Cell Wall:
Gives cells shape and
support and provides
protection.
Found in algae, fungi
and most bacteria too.
contain all of the previous organelles (except centrioles)
as well as:
Plant Cells:
Chloroplast: (green)
Changes sun’s energy as
well as CO2 and H2O into
food.
Also in green algae.
contain all of the previous organelles (except centrioles)
as well as:
Plant Cells:
Central Water Vacuole:
Single, large water filled
vacuole in the middle of
the cell.
Strengthen cells and
provide support for
plant.
Contains toxins to harm
plant predators, waste
products and pigment
for color (petals).
contain all of the previous organelles (except centrioles)
as well as:
Plant Cells:
Central Water Vacuole:
contain all of the previous organelles (except centrioles)
as well as:
What do YOU think?
Would it be accurate to say that a chloroplast
makes energy for a plant cell? Explain.
What are the similarities and differences
between plant and animal cells?
How do the parts of a cell make it function as
a system?
Unicellular (one) vs.
Multicellular (many)
Unicellular: Single-Celled
Most common forms of
life on Earth.
Carry out all functions
of Life.
Bacteria
Amoeba
Paramecium
Unicellular (one) vs.
Multicellular (many)
Multicellular
Larger organisms.
Different cells have
specialized functions,
together making a
complete organism.
Human
Spider
Jellyfish
Visit a “Tour of the Cell” at:video